Blowpipe.



` Pa'tbnted Sept-26, |899. T. G. LEWIS.

BLDWPIPE.

(Application led Apr. 15, 1899.)

(Nadel.)

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' UNITED "STATES- PATENT VrelicsQ THEODORE G. LEWIS, OF BUFFALO, NEWT YORK, ASSIGNOR TO THE BUFFALO DENTAL MANUFACTURING COMPANY, SAME PLACE.

eLowPlPE.

I SPEIFIGATION forming part of Letters Patent No. 633,859, dated September 26, 1899.

Application ledApril 15, 1899. Serial No. 713,181. (Model.)

To alt whom it may concern:

Be it known that. I, Tnnonoan G. Lewis, a citizen of the'Uuited States, residing at Buf-V falo, in the counly'of Erie and State of New York, have invented new and useful Improvements in Blowpipes, of which the following is a specification.

This invention relates to a blowpipe intended more especially for use in connection xo with gasolene-gas, although the saine may be used with any other suitable gas, if desired. The object of my invention is the production of a blowpipe in which the gas iscon- .centrated and confined around the air-jet of the blowpipe in such a manner that the llame is not liable to be extinguished by an excessive blast.

In the accompanying drawings, Figure 1 is a side elevation of my improved blowpipe. zo Fig. 2 is a longitudinal section, on an enlarged scale, of the burner of the blowpipe. Figs. 3 and 4 are cross-sections in lines 3 3 and 4 4, Fig. 2. Fig. 5 is a longitudinal section similar to Fig. 2, showinga modied construction of the gas-eonfningV hood.

Like letters of reference refer to like Iparts in the several igures.

A is the body or main gasp-tube of the blowpipe, which has its rear end connected with 3o a gasolene-gasgenerato'r or other source of supply by the usual hose, which is not shown in the drawings.

B is a hollow head or L-shaped casing or iitting having its inner branch secured to the 3 5 front end of the main gas-tube A, preferably by a screw-threaded joint, as shown, and C is a hollow boss arranged on the upper side of said head and provided in its rear side with an opening or passage with which the usual 4o air-blast pipe D of the blowpipe is connected. In practice this air-pipe is connected with a foot-b1ower or other air-forcing device or with a tank containing compressed air in a wellknown manner. E is a gas-delivery nozzle or tube secured at its inner end to the outer end of the head B, preferably by a screw-thread, and communieating with the chamber of the head, so as to receive the gas therefrom. This gas-nozzle is 5o somewhatcontracted atit-s outerend,as shown at e, and provided in its sides near its outer end with an annular row of gas outlets or ap ertnres e', through which the gas issues Vlaterally `from the nozzle.

F is an air tube or nozzle arranged centrally-within the gas-delivery nozzle E and the outer branch ot' the head B and secured at its open inner end in an opening f, which communicates with the cavity ofY the hollow boss C, so that the air entering said cavity 6o through the blast-pipey D passes into and through the air-tube YF. The nipple or front end ofthe 4air-tube is tapered in the usual manner and extends a short distance beyond the surrounding gas-delivery nozzle E, as shown in Fig. 2. The air-tube is considerably smaller in diameter than the bore of the gas-'nozzle to leave an annular space between these tubes for the passage of the gas. The

contracted front end of the gas-nozzle is sepa- 7o i rated from the adjacent front portion of the air-tube' by an annular gas-passage g.

H is an annular gathering hood or sleeve which surrounds the front portion of the gasnozzle E andvair-tube F and serves to conine the gas which issues from the lateral outlets c of the gas-nozzle around the air-tube and directs such gas forwardly or toward the mouth of the gas tube for sustaining the flame of the blowpipe. The rear portion of 8o this confining-hood is tted closely upon the gas-nozzle E and abut-s at is rear end against the outer end of the head B, so as to close the rear end of the hood and prevent the entrance of the externalair at this point. The hood is also closed on all sides for the same purpose. Thebore of the hood is enlarged from a point in rear of the lateral gas-outlets e' ofthe gas-nozzle to the front end of the hood, as shown at 71 to form an annular gas- 9o space between said nozzle and the hood. This enlargement is preferably formed by daring the bore of the hood, as shown in Fig.

2; but the enlargement may be of cylindrical form, if desired, as shown in Fig. 5. The hood extends a short distance beyond the gasnozzle, as shown in Fig. 2.

When gas and air are supplied to the blowpipe, a portion of the gas'entering the gasdelivery nozzle E issues forwardly in an annu- :oo lar sheet or column through the contracted space between the front end of the gas-nozzle i l l i andthe air-nozzle F, While the remaining portion of the gas passes laterally through the side opening e of the gas-nozzle into the surrounding hood H, which confines the gas and deflects the same forwardly in proximity to the air-jet, producing an outer annular sheet of gas, which surrounds the inner sheet issuing at the front end of the gas-nozzle. These concentric envelops of gas unite at or near the front end of the air-nozzle and com mingle With the air-jet, producing a thorough mixture of gas and air, while the surrounding hood holds the gas in intimate relation to the air-jet, thereby supporting combustion and maintaining a Iiame under all conditions of air-pressure. It has been demonstrated that this improved construction of the burner prevents extinguishing of the flame by an excessive or over pressure of air, avoiding the blowing out of the flame at a critical moment and rendering the blowpipe very reliable in use. By closing the confining-hood yat its rear end and on all sides the admission of external air to the hood is prevented, and the size and form of the flame can be regulated by the usual valve of the blowpipe without affecting the intensity of the fiame which would result from supplying air to the hood.

I is the usual regulating-valve, arranged in the main gas-tube of the blowpipe, and j the projecting stem of the valve.

I claim as my inventionl. In a burner for a blow-pipe, the combi- Y nation with aV casing having gas and air inlets or chambers, of a gas-delivery nozzle communicating with said gas-inlet and provided near its front end with lateral gas-outlets, an air tube or nozzle arranged Within said gas-nozzle and communicating With the air-inlet of the burner-casing, and a confining-hood surrounding said gas-nozzle and separated therefrom by an intervening gasspace and closed at its rear end and on all sides, substantially as set forth.

2. In a burner for blowpipes, the .combination with a casing having gas and air inlets or chambers, of a gas-delivery nozzle communicating with said gas-inlet and provided near its front end with lateral gas-out- Ylets, an airtube or nozzle arranged Within said gas-nozzle and communicating with the air-inlet of the burner-casing, and an imperforate confining-hood surrounding said gasnozzle, the front portion of the bore of said hood being enlarged to form a gas-space between the gas-nozzle and the hood and the rear portion of the hood being closely fitted upon the gas-nozzle, whereby the rear portion of the hood is closed, substantially as set forth. Y

Witness my hand this 12th day of April, 1899.

THEODORE G. LEWIS. YVitnesses:

' CHAs. O. ROTHER, CARL F. GEYER. 

